1. Field of the Invention
The invention is directed to a method for the operation of an internal combustion engine having a plurality of cylinders, namely, a method for cylinder-specific combustion control in at least some cylinders, preferably all of the cylinders, of the internal combustion engine.
2. Description of the Related Art
Internal combustion engines must meet increasingly stricter emission limit values. One possibility for meeting these emission limit values is to optimize the operation of the internal combustion engine by a control. In this regard, it is also already generally known in internal combustion engines to control the individual cylinders of the internal combustion engine individually.
DE 10 2005 058 820 A1 discloses a method for operation of an internal combustion engine, particularly a self-igniting internal combustion engine, in which at least one quantity characterizing a respective course of combustion in an associated combustion chamber is calculated in a cylinder-specific manner. The controlling of cylinder-specific fuel injection parameters is influenced depending on this at least one quantity characterizing the combustion curve. This is carried out in that a cylinder pressure is measured at the cylinders so that a quantity characterizing the combustion in the respective cylinder can be calculated depending on the cylinder pressure measurement. Actual combustion values calculated in this way are compared with corresponding reference combustion values in order to influence cylinder-specific fuel injection parameters depending on a control deviation as control variables for the cylinders.
When the actual combustion values are calculated, for example, from the measured cylinder pressure as proposed in DE 10 2005 058 820 A1, the combustion in the cylinders of the internal combustion engine can only be optimized to a limited extent for complying with emission limit values. This is because, among other things, no information about wear or about changes in the injection characteristics of fuel injection nozzles can be gained from the cylinder pressure.